Patients with Gaucher disease suffer from a lack of functional glucocerebrosidase enzyme (Gc). This study is designed to determine if cDNA encoding normal Gc can be introduced into macrophage precursors using a retroviral vector. CD34+ cells obtained from GCSF mobilized peripheral blood stem cells or from bone marrow will be transduced ex-vivo. These transduced cells will be reinfused into the patient who will be monitored for toxcities as well as evidence of successful transfer and expression.